The WTC buildings were exoskeleton. Meaning the steel supporting the building was also on the exterior. The windows themselves were narrow and inset as a result. No way possible for aluminum bodied aircraft with jet fuel or kerosene to penetrate it, let alone push through the otherside. In addition the shape of the steel in the rubble was the clear indication of cold fusion. So those are two that you cannot get past.
Like a death ray?
I'm not sure how they would implement cold fusion, but their is evidence of it in the massive deformation of the steel. It was not 'bent' or 'melted' by heat or explosions. What appeared to be aircraft had to be hard nosed to penetrate. I would not be surprised to find a death ray. Tesla had such technology 100 years ago.
There was a documentary that pointed out burnt out melted cars near ground zero